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Interpretation ID: 001389Klasing.drn

    Tony Klasing, Manager
    Vehicle Inspection Unit
    Division of Traffic Safety
    Illinois Department of Transportation
    3215 Executive Park Drive
    P. O. Box 19212
    Springfield, IL 62794-9212

    Dear Mr. Klasing:

    This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 217, Bus emergency exits and window retention and release. Specifically, you wish to know whether in test procedures for school buses specified at S5.4.2.1(a)(1) of the standard, a parallelepiped is used or a template. The answer is the agency uses a parallelepiped, as specified in the standard, rather than simply measuring from the rear of the seat back to the exit door.

    As specified at S5.4.2.1(a), the rear emergency exit door must be manually extendable by a single person to a position that permits "an opening large enough to permit unobstructed passage of a rectangular parallelepiped 114 centimeters high, 61 centimeters wide, and 30 centimeters deep" when "keeping the 114 centimeter dimension vertical, the 61 centimeter dimension parallel to the opening, and the lower surface in contact with the floor of the bus at all times."[1]Contrary to what may be your understanding, the agency has not "approved" the use of a template that tapers at the top.

    I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama of my staff at this address or at (202) 366-2992.


    Jacqueline Glassman
    Chief Counsel


    [1] In some school buses, the rear of the bus may curve inward, towards the passenger compartment. In such cases, in testing, although the bottom of the parallelepiped is in contact with the floor of the bus at all times, the top part of the parallelepiped may extend outside of the bus. When it conducts its school bus compliance testing for the rear emergency exit door, NHTSA would deem the school bus to meet S5.4.2.1(a)(1) of Standard No. 217 as long as the bottom of the specified parallelepiped is in contact with the floor of the bus at all times.